Buggy code:
public class TileEntitySieveAutomatic extends TileEntity implements IEnergyHandler , ISidedInventory { public EnergyStorage storage = new EnergyStorage ( 64000 ) ; private int energyPerCycle = ModData . sieveAutomaticBaseEnergy ; private static final float MIN_RENDER_CAPACITY = 0.7F ; private static final float MAX_RENDER_CAPACITY = 0.9F ; private float PROCESSING_INTERVAL ; private static final int UPDATE_INTERVAL = 20 ; private int speedLevel ; private static Random rand = new Random ( ) ; protected ItemStack [ ] inventory ; public Block content ; public int contentMeta = 0 ; private float volume = 0 ; public TileEntitySieveAutomatic . SieveMode mode = TileEntitySieveAutomatic . SieveMode . EMPTY ; private int timer = 0 ; private boolean update = false ; private boolean particleMode = false ; public enum SieveMode { EMPTY ( 0 ) , FILLED ( 1 ) ; private SieveMode ( int v ) { } public int value ; } public TileEntitySieveAutomatic ( ) { } public void changeSpeedLevel ( float change ) { } public void addSievable ( Block block , int blockMeta ) { } @ Override public void updateEntity ( ) { } public void ProcessContents ( ) { } @ SideOnly ( Side . CLIENT ) private void spawnFX ( Block block , int blockMeta ) { } public float getVolume ( ) { } public float getAdjustedVolume ( ) { } private void update ( ) { } private void disableParticles ( ) { } @ Override public void readFromNBT ( NBTTagCompound compound ) { } @ Override public void writeToNBT ( NBTTagCompound compound ) { } @ Override public Packet getDescriptionPacket ( ) { } @ Override public void onDataPacket ( NetworkManager net , S35PacketUpdateTileEntity pkt ) { } @ Override public boolean canConnectEnergy ( ForgeDirection from ) { } @ Override public int receiveEnergy ( ForgeDirection from , int maxReceive , boolean simulate ) { } @ Override public int extractEnergy ( ForgeDirection from , int maxExtract , boolean simulate ) { } @ Override public int getEnergyStored ( ForgeDirection from ) { } @ Override public int getMaxEnergyStored ( ForgeDirection from ) { } @ Override public int getSizeInventory ( ) { } @ Override public ItemStack getStackInSlot ( int slot ) { } @ Override public ItemStack decrStackSize ( int slot , int amount ) { } @ Override public ItemStack getStackInSlotOnClosing ( int i ) { } @ Override public void setInventorySlotContents ( int slot , ItemStack stack ) { } @ Override public String getInventoryName ( ) { } @ Override public boolean hasCustomInventoryName ( ) { } @ Override public int getInventoryStackLimit ( ) { } @ Override public boolean isUseableByPlayer ( EntityPlayer par1EntityPlayer ) { } @ Override public void openInventory ( ) { } @ Override public void closeInventory ( ) { } @ Override public boolean isItemValidForSlot ( int slot , ItemStack item ) { } @ Override public int [ ] getAccessibleSlotsFromSide ( int side ) { } @ Override public boolean canInsertItem ( int slot , ItemStack item , int side ) { } @ Override public boolean canExtractItem ( int slot , ItemStack item , int side ) { <START_BUG> if ( slot >= 1 ) <END_BUG> return true ; return false ; } public float getEffectiveSpeed ( ) { } public int getEffectiveEnergy ( ) { } public int getFortuneModifier ( ) { } }

Fix:
if ( ( slot >= 1 ) && ( slot < 21 ) )